Reference ancestor_hierarchies in depth instead of ancestors

[weilandia]

This is helpful because we can more easily eager load ancestor_hierarchies than we can ancestors to avoid n + 1 queries.

tag = Tag.includes(:ancestor_hierarchies).first
tag.depth

[seuros]

Sounds good, can you add a changelog entry ?

[weilandia]

@seuros long delay here :) but I added to changelog. Can we could get this pr merged?

[seuros]

Great

[Tranquility]

Why do you even need the includes? ancestors is a single query that returns all the ancestors.

[Tranquility]

This code actually changes the behavior ancestor_hierarchies includes the self and ancestors does not. So this increases the result by 1.

[seuros]

should we just do ancestor_hierarchies - 1 ?

[Tranquility]

I don't understand why this change is needed at all.

[weilandia]

This makes it so you can call depth on a node in a collection without an n+1 query (except it is off by 1 🤦).

Tag.includes(:ancestor_hierarchies).map(&:depth)

[seuros]

@weilandia can you fix it and add a small test ? i will release a new version.

[weilandia]

#435